The invention relates to a circuit breaker with a sealed enclosure filled with a high dielectric strength gas and containing one or more poles of the circuit breaker, each pole comprising:
a breaking chamber having a revolution surface tightly sealed at both its ends by end plates
a pair of tubular arcing contacts, coaxially arranged in said breaking chamber and each passing through one of said end plates to make the breaking chamber communicate, in the separated position of the arcing contacts, with said enclosure forming an expansion chamber via the gas outflow channels constituted by the tubular arcing contacts
a coil or a permanent magnet supported by one of said end plates inside the breaking chamber so as to create in the arcing contact separation area a magnetic blowout field by rotation of an arc drawn between the separated arcing contacts
a pair of main contacts disposed outside the breaking chamber and arranged to open before the arcing contacts separate when a circuit breaker opening operation takes place.
A state-of-the-art circuit breaker combines pneumatic arc blowout by expansion gases with magnetic arc blowout by rotation on annular electrodes. This breaking method can be used in medium or high voltage circuit breakers and has the advantage of requiring low operating forces. It has already been proposed to fit, in addition to the arcing contact ensuring breaking of the current, main contacts conducting the rated current and opening before separation of the arcing contacts takes place. These state-of-the-art devices are complicated and require elaborate electrical connections.
The object of the invention is to achieve a circuit breaker of particularly simple structure and architecture enabling the current conducting and breaking functions to be separated.